Field of the Disclosure
Embodiments of the disclosure generally relate to a system for conveying tubulars from a catwalk onto a rig floor, and from the rig floor back onto the catwalk.
Description of the Related Art
In a drilling or rig work-over operation, whether on a water-based or a land-based drilling rig, drill pipe, casing, conductor pipe, or other tubulars are often stored at a storage level, that is at a lower elevation than the rig floor because rig floor space is limited. Operators typically use a catwalk to convey the tubulars between the storage level and the rig floor. The tubulars are positioned in a trough of the catwalk, raised to an elevation near the rig floor, and conveyed (e.g., pushed and/or pulled) from the trough onto the rig floor.
Specifically, each tubular is moved and raised to the rig floor by the catwalk in a substantially horizontal or slightly angled position. A leading end (e.g. the upper end) of the tubular is then engaged by a hoist and raised from the trough. As the leading end of the tubular is being raised, the tailing end (e.g. the lower end) of the tubular is pushed and/or dragged along the trough. When the tailing end of the tubular reaches the end of the trough, the tailing end of the tubular may swing off of the trough and over the rig floor (for example, like a pendulum) until the tubular stabilizes and raised into a substantially vertical position by the hoist. In this manner, the tubular is moved from a substantially horizontal position to a substantially vertical position onto the rig floor.
A separate tailing system is used to help guide the tailing end of the tubular when moving from the end of the trough onto the rig floor to prevent uncontrolled swinging of the tubular. One problem with existing tailing systems is that they cannot accommodate tubulars of variable ranges and sizes, and therefore inserts and other parts are required to be used depending on the size of tubular required on the rig floor. Additionally, other hardware may be required to be changed out, thus creating additional processes that must be completed to transition between tubulars of different sizes. Other problems include unsafe guiding and controlling tubulars between the substantially horizontal or slightly angled position and the substantially vertical position, as prior art systems require a deck hand using a rope, chain, and/or additional equipment to control and stabilize the swing of the tubular.
Accordingly, it would be useful to have one system to accommodate and guide tubulars of varying sizes between a substantially horizontal or slightly angled position and a substantially vertical position in a hands-off and seamless operation, which requires no change in hardware or additional equipment and provides increased safety.